Automatic Bobbin Winding with Residual Thread Detection
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Solution Overview
Problem
Existing automatic bobbin winding processes lack quality assurance for ensuring precise thread lengths and bobbin dimensions, often resulting in bobbins with residual thread, which affects the reliability of the sewing process.
Innovation Solution
An automatic winding process with a residual thread sensor system that includes optical, tactile, and length/revolution counter sensors to detect and prevent residual thread, ensuring bobbins are wound to precise specifications, and a fill level sensor to verify complete winding.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If automatic bobbin winding is performed without residual thread detection, then the winding process is simple and fast, but the thread length precision and bobbin quality are poor
Solution Approach 1:
The system performs preliminary detection of residual thread on the bobbin before the winding process begins. The residual thread sensor checks whether the bobbin is empty or contains remaining thread, and only allows winding to proceed when the bobbin is confirmed empty. This preliminary action ensures that each winding cycle starts from a known state, guaranteeing precise thread length without requiring complex real-time monitoring during winding.
Solution Approach 2:
The winding system incorporates feedback through residual thread detection both before and after the winding process. The sensor provides information about the bobbin state, and the control unit uses this feedback to determine whether to initiate winding and whether the winding was successful. This closed-loop feedback ensures precise thread length control while maintaining relatively simple system architecture.
2Manufacturing precision
If residual thread detection is implemented, then bobbin quality and thread length accuracy improve, but the winding process time increases
Solution Approach 1:
The residual thread detection is performed as a quick preliminary check at the start of each winding cycle before the actual winding begins. The sensor rapidly determines whether the bobbin is empty, and the control unit immediately decides whether to proceed. This preliminary action minimizes time loss by performing detection only once at the beginning rather than continuously during winding, while still ensuring precise bobbin dimensions.
Solution Approach 2:
The system automatically performs residual thread detection and control decisions without requiring manual inspection or intervention. The residual thread sensor and control unit work together to autonomously determine whether winding should proceed, eliminating time-consuming manual checks while maintaining precise bobbin dimension control.
3Reliability
If multiple sensor types are used for residual thread detection, then detection reliability improves, but device complexity and cost increase
Solution Approach 1:
The winding system is designed to accommodate multiple types of residual thread sensors (optical, tactile, electromagnetic) that can be selected based on specific application requirements. Each sensor type serves the same universal function of detecting residual thread, allowing the system to achieve high detection reliability through appropriate sensor selection without requiring integration of multiple sensor types simultaneously. The control unit is designed to work with various sensor interfaces, providing multi-functionality.
Solution Approach 2:
The system offers non-mechanical sensing options such as optical and electromagnetic sensors to replace traditional tactile mechanical sensors for residual thread detection. This substitution reduces mechanical wear and increases detection reliability while maintaining relatively simple device architecture. The optical sensor uses light absorption differences, and the electromagnetic sensor uses electrical conductivity differences, both providing reliable detection without mechanical contact.
4Manufacturing precision
If fill level detection is added to the winding system, then quality assurance improves, but the device complexity increases
Solution Approach 1:
The existing residual thread sensor serves dual functions: it detects both residual thread (by checking if the bobbin is empty) and fill level (by monitoring the bobbin state throughout the winding process). The same sensor that determines whether winding should start also verifies when winding is complete, eliminating the need for separate fill level detection hardware. This multi-functionality maintains manufacturing precision while avoiding additional device complexity.
Solution Approach 2:
The system merges the residual thread detection function with the fill level detection function into a single integrated sensing and control system. The control unit uses the same sensor input to make both decisions: whether to start winding (residual thread detection) and when to stop winding (fill level detection). This merging of functions achieves precise bobbin fill level control without adding separate sensor systems.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
Ensures bobbins are wound with precisely defined thread lengths and dimensions, preventing residual thread and ensuring accurate sewing, while also allowing for reliable detection of fill levels for both current and previously wound bobbins.
Implementation Method 1
An automatic winding process with a residual thread sensor system that includes optical, tactile, and length/revolution counter sensors
Implementation Method 2
An optical remaining thread sensor according to claims 3 to 5 can be designed with high precision. The light source and the light detector can be combined in one unit
Data Source
Figure 1
Figure 2~3
Figure 4
AI summary
The method involves inserting a coil (13) into a coil retainer of a reeling device (8), and determining residual thread on the inserted coil by using a residual thread sensor (16) i.e. light barrier sensor. The coil is wound or the coil is released only when the inserted coil carries no residual thread. A signal transmitter (17) is connected with the sensor, where the sensor is provided with a light source and a light detector. A surface of the coil is used as a reflector in a light path between the light source and the light detector. An independent claim is also included for a reeling device for executing a method for automatically winding a coil from a thread spool.